v1.1.3Published 2 years ago

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Measure FPS

While working with CSS, HTML, and JavaScript, it's always important to take care of browser rendering in browser DevTools. To find issues with rendering, we are using "Timeline" with "JS Profile" and "Memory" consumption tracking. Those tools are great when you know about the existing problem.

During our development process, we are using FPS-meter, which gives a signal when "Long" frames occur. To see meter action, visit this link (in the left bottom corner). Play with sliders to see how different CSS effects may slow down the rendering process, blur is the most "expensive" CSS3 filter.

This library works on mobile devices. It utilizes performance.now to measure time frame and requestAnimationFrame to measure rendered frames, both APIs are very efficient and have a minor impact (for correct FPS measurement).


  • Demo can be found on this website (in the left bottom corner).

Drop-in version

Installation is not required, copy-paste script into browser' console:


Installation is available via NPM for your favorite build tool and Atmosphere for Meteor.js

NPM install

npm i --save fps-m

Meteor add

meteor add ostrio:fps-meter

NPM require

1// require
2const FPSMeter = require('fps-m');
4// ES6 import:
5import FPSMeter from 'fps-m';

Meteor: ES6 Import

1import { FPSMeter } from 'meteor/ostrio:fps-meter';

Quick start

1(new FPSMeter({ui: true})).start();


Render, start, pause, and resume FPS Meter

new FPSMeter([opts])

  • opts {Object}
  • opts.ui {Boolean} - Render small box with current FPS into body, default: false
  • opts.reactive {Boolean} - Store current FPS as reactive data source, default: false
1// Quick start:
2const fps = new FPSMeter({ui: true, reactive: false});
3// fps.start();
4// fps.stop();


  • FPSMeter#start() — Use to start measuring FPS. If {ui: true} small box with current FPS will be rendered into body
  • FPSMeter#stop() — Use to stop measuring FPS. If {ui: true} box with current FPS will be removed from body
  • FPSMeter#pause() — Use to pause measuring FPS. If {ui: true} box with current FPS will remain in body
  • FPSMeter#resume() — Use to resume measuring FPS
  • FPSMeter#toggle() — Use to toggle (pause/resume) measuring FPS


  • FPSMeter#isRunning {Boolean} — true if meter is running and false when meter is on pause, stopped or has not started yet
  • FPSMeter#template {Blaze.View|undefined} — When {ui: true} this property holds Blaze.View instance, otherwise its undefined
  • FPSMeter#element {DOMElement|undefined} — When {ui: true} this property holds DOMElement of FPSMeter UI element div, otherwise its undefined
  • FPSMeter#fps {Number|ReactiveVar} — When {reactive: false} it holds a {Number} with current FPS. When {reactive: true} it is an instance of {*ReactiveVar*}. Use .get() method to return current FPS. It's reactive data source, and can be used in template:


Pause/Resume by clicking on UI box

1const fps = new FPSMeter({ ui: true });
3fps.element.addEventListener('click', fps.toggle.bind(fps), { passive: true, capture: false });

Meteor.js usage

1const fps = new FPSMeter({ui: false, reactive: true});
4  currentFPS() {
5    return fps.fps.get();
6  }
10  'click [data-start-fps]'(e) {
11    e.preventDefault();
12    fps.start();
13    return false;
14  },
15  'click [data-stop-fps]'(e) {
16    e.preventDefault();
17    fps.stop();
18    return false;
19  }
1<template name="currentFPS">
2  <div>{{currentFPS}}</div>
3  <button data-start-fps>Start</button>
4  <button data-stop-fps>Stop</button>

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